The term "phospholipid" is generic to several different types of compounds originating in the mammalian cell and containing long chain fatty acid esters of glycerol attached to various polar groupings. Lecithin, a phosphatidic acid ester of choline, is one of a group of phospholipids of structure I below ##STR1## wherein Z and Z.sup.1 are long, straight-chain alkyl or alkenyl radicals and ##STR2## A related substance is platelet-activating factor (PAF)--see Demopoulos et al, J. Biol. Chem., 254, 9355 (1979)--having structure Ia below ##STR3## in which there is an ether linkage on C-1, a short chain fatty acid ester (acetate) at C-2, Z is C.sub.16 -C.sub.18 alkyl and Q has its previous meaning. A number of analogues of PAF have been synthesized. Among these are compounds of structure Ib below described in FEBS Letters, 14 29 (1982), see also Modell et al, Can. Res., 39, 4681 (1979) which describes the activity of such compounds in selectively destroying Meth A sarcoma cells. EQU Z--O--CH.sub.2 --CH--Z.sup.2 --CH.sub.2 --Q Ib
where Z.sup.2 is alkyl or H; and Q has its previous meaning.
Other substitutions such as chloro for the C-2 acyloxy of PAF are known.
Diethers of structure Ic are also known-- ##STR4## See U.S. Pat. No. 4,426,525 where Z is tridecyl or tetradecyl.
The compound wherein Z is C.sub.18 H.sub.37 and Z.sup.2 is methyl inhibits the proliferation of leukemic cells according to Tidwell et al., Blood, 57, 794 (1981)--see also Derwent Abstract 17735 K/08 and Derwent Abstract 98882 E/46.
Compounds lacking the C-1 oxygen have also been prepared; ie., compounds of the structure EQU Z--CH.sub.2 --CHOH--CH.sub.2 --Q Id
where Z is C.sub.13 --H.sub.27 (CAS 51814-79-0); Z is C.sub.12 H.sub.25 and the C-2 hydroxyl is esterified (CAS 54646-41-2) and Q has its previous meaning--see also Derwent Abstract 12632 K/06 (an ortho ester) and Chang, et al. Biochem. and Biophys. Res. Comm; 54, 648 (1973) particularly Scheme 1, page 652, and related disclosure.
Ethers of compounds according to Id have recently been disclosed in EPO application 92,190 published Oct. 26, 1983 based on G.B. 82-11284 filed Apr. 19, 1982, as represented by formula Ie EQU Z--CH.sub.2 --CHOZ.sup.1 --CH.sub.2 Q Ie
where Z is alkyl, alkoxy or alkanoylamino and Z.sup.1 is lower alkyl, lower alkanesulfonyl or arenesulfonyl; dl-2-methoxy-1-[(2-trimethylaminoethoxy)phosphinyloxy]-octadecane, hydroxy inner salt, is specifically disclosed. The compounds are alleged to inhibit the growth of Meth A sarcoma transplanted in mice.
Compounds according to Ie in which Z contains one or more unsaturations (double or triple bonds) are not known, nor will the procedure of EPO 92190 furnish such compounds.